The correct answer is: A. Kalka-Shimla.
The Kalka-Shimla railway line is a 96.6-kilometer (60.4 mi) narrow-gauge railway line in India. It is one of the world’s highest railways, with an elevation of 2,076 meters (6,811 ft) at its highest point. The line was built between 1891 and 1903 and is a UNESCO World Heritage Site.
The line runs from Kalka in Haryana to Shimla in Himachal Pradesh. It is a single-track line with 107 tunnels and 869 bridges. The line is operated by the Indian Railways.
The Kalka-Shimla railway line is a popular tourist destination. The line offers stunning views of the Himalayas. The line is also a popular destination for railway enthusiasts.
The other options are incorrect because they are not broad gauge railway lines. A broad gauge railway line is a railway line with a track gauge of 1,676 mm (5 ft 6 in). The other options are all narrow gauge railway lines. A narrow gauge railway line is a railway line with a track gauge of less than 1,435 mm (4 ft 8 1â2 in).